The C5 is a lightweight, affordably priced hub designed for durability Built around proven 3/8` axle bolts, a strong, chromoly female axle and solid sealed cartridge bearings Two plastic guards are included 15mm 4130 chromoly female axle 3/8` heat-treated chromoly axle bolts w/17mm wrench flats and 6mm hex slots 6902 sealed cartridge bearings 6061 T-6 aluminum hub shell